1. Field of the Invention
The present invention relates to a measuring instrument. Specifically, it relates to a measuring instrument mounted with a plurality of probes.
2. Description of Related Art
When, for instance, a plurality of measuring portions on an object to be measured are measured using a single measuring instrument, the most appropriate probe is required to be used for measurement according to shapes of the measuring portions, measuring items, required measuring accuracy and the like. For this purpose, a measuring instrument provided with a so-called probe exchange function is also proposed, where a probe stocker storing a plurality of probes is provided and an appropriate probe for the measurement is selected to be exchanged.
However, in order to exchange the probes, the probe holder has to be moved to the position of the probe and, subsequently, the probes have to be exchanged between the probe holder and the probe stocker, which takes considerable time.
Accordingly, a measuring instrument mounted with a plurality of probes in advance in a probe holder is also proposed (see, for instance, Document 1: JP-A-11-142141).
Conventionally, when a plurality of probes are mounted on a probe holder, e.g. when, as shown in FIGS. 7 and 8, three probes of a laser displacement probe 9A, a touch signal probe 9B and an image probe 9C are mounted on a probe holder 102 provided on a Z-axis slider 101 of a coordinate measuring machine, three probes are juxtaposed with a predetermined interval in a direction (e.g. X-axis direction) perpendicular to a movable direction (e.g. Z-axis direction) of the probe holder 102.
However, juxtaposition of the three probes (the laser displacement probe 9A, the touch signal probe 9B and the image probe 9C) results in offset of the probes 9A, 9B and 9C in the X-axis direction, which will lead to narrowing measurable ranges in common with the probes and increasing Abbe's error by the offset in the X-axis direction.
Moreover, when relative moving ranges between the object to be measured and the probes 9A, 9B and 9C are expanded so as to broaden the measurable ranges, the size of the instrument is increased.